Background art in this technological field include Japanese Unexamined Patent Application Publication No. 2005-180298 (Patent document 1). This publication refers to “a scroll compressor in which the volute center of the orbiting scroll volute body and the volute center of the fixed scroll volute body are disposed in positions shifted, relative to the centers of the end plates of the orbiting scroll and the fixed scroll, in the direction of a straight line linking the winding end positions of the two volute bodies to the volute center of the Archimedean spiral curve or the envelope thereof” (see Claim 1 of the publication).
Another case of relevant background art is found in Japanese Unexamined Patent Application Publication No. Hei8-232863 (Patent document 2), which contains a mention of “a shaft penetrating scroll compressor in which an orbiting bearing part is disposed in the central part of an orbiting scroll member and an eccentric shaft part of a crankshaft is inserted into the orbiting bearing part to the lap tip part” (see Claim 1 of the publication).